Porous biomaterials are used in a variety of implantable medical devices, including sutures and vascular grafts. Implants frequently induce a foreign body response that results in the formation of an avascular, fibrous capsule around the implant, which limits the performance of many implants. It has been shown that the biological response to implanted biomaterials is dependent on the microarchitecture of the biomaterial (see, e.g., Brauker et al. (1995) J. Biomed. Mater. Res. 29(12):1517-24; Sharkawy et al. (1998) J. Biomed. Mater. Res. 40:586-97). There is a continuing need for porous biomaterials that promote vascularization in and around the implant and reduce the foreign body reaction.